Pyridyl azides and derivatives thereof

ABSTRACT

THE INVENTION IS A GROUP OF COMPOUNDS OF THE FORMULA   (X)N,(Y)P,(N3)M-PYRIDINE   WHEREIN X IS HALOGEN; Y IS NITRILE, CARBOXAMIDE, CARBOXYL, ESTER OR TRIHALOMETHANE; M IS 1-4; N IS 0-4; P IS 0-2; AND M+N+P IS 2-5. THE COMPOUNDS, WHICH GENERALLY MAY BE PREPARED BY INTRODUCING THE AZIDE MOIETY BY EXCHANGE WITH A RING HALOGE, HAVE BEEN FOUND TO BE USEFUL AS HIGH ENERGY COMPOUNDS, SUCH AS DETONATORS.

United States Patent ABSTRACT OF THE DISCLOSURE The invention is a group of compounds of the formula wherein X is halogen; Y is nitrile, carboxamide, carboxyl, ester or trihalomethane; m is 1-4; n is 0-4; p is 0-2; and m-l-n-l-p is 2-5. The compounds, which generally may be prepared by introducing the azide moiety by exchange with a ring halogen, have been found to be useful as high energy compounds, such as detonators.

SUMMARY OF THE INVENTION The invention is a group of compounds of the formula wherein each X is, indenpendently, Cl, Br, I or F; Y is (each R independently being H, aryl (phenyl or naphthyl) or an alkyl group of up to about 18 carbon atoms), COOH or COOR' (R being the residue of an esterifiable organic hydroxy compound-such as alkyl, aryl, alkaryl and aralkyl esters with up to 18 carbons in the alkyl portion); m is 1 to 4; n is 0 to 4; p is 0 to 2; and the sum of m +n+p is from 2 to 5.

The compounds of this invention may be prepared from known starting materials by exchanging an active ring-substituted halogen for an azide. They may also be prepared by diazotization of a ring-substituted amine group, with subsequent exchange of said azo group for an azide group.

The compounds have been found to be useful as high energy compounds, such as detonators, propellants, and the like.

Those compounds in the above formula wherein m is 3 to 4, Y is CN, p is 1 to 2 and n is 0 are preferred.

DETAILED DESCRIPTION OF THE INVENTION The compounds of the invention are prepared by replacing one or more ring-substituted halogens with an azide. Metal azides, such as NaN or KN are suitable for said replacement.

The reaction conditions depend upon the reactivity of the particular pyridine compound in question. A reactive halogen compound, such as 2-cyano-3,4,5,6-tetrachloropyridine, will react readily with room temperature, overnight stirring of a methanolic solution of the reactants. Less reactive materials will either require longer reaction times, higher reaction temperatures or the use of a more favorable solvent, such as dimethylformamide. No effort should be made to force the reaction by use of severe conditions until trial micro-experiments furnish definite 3,773,774 Patented Nov. 20, 1973 knowledge regarding the stability of the resulting azide reaction products. Generally speaking, a direct relationship exists concerning instability and the number of azide groups per molecule, the monoazide compounds usually being the most stable.

The degree of substitution is dependent upon the relative quantity of metal azide used and whether the pyridine compound contains activating groups or easily replaceable halogen, especially a halogen in the two position.

The normal reaction course involves a stepwise reaction sequence, the four or para position generally being the most reactive, followed by the two and six positions. A different reaction mechanism occurs once a two or six position is substituted with an azide group. The overall sequence is generally as follows:

X N z I X- X X X I NaNa I X- X X -X N N one mole one mole predominately III NaNa It is to be noted that compound III is in equilibrium with the adjacent heterocyclic nitrogen and forming a tetrazole. This azide-tetrazole transformation profoundly alters the reactivity of the remaining ring halogens with the six-position chlorine atom reacting as soon as compound III forms. The final result is that compound III is generally a transitory intermediate.

Trichloromethylor trifluoromethyl-substituted pyridyl azides, with or without halogen substituents, may be prepared from, for instance, 3amino-3,5,6-dichloro-2-trichloromethylpyridine (U.S. Pat. 3,224,950); 2,3,4-trichloro-2trichloromethylpyridine (U.S. Pat. 3,256,167); 6- chloro-2-trichloromethylpyridine (U.S. Pat. 3,418,323); and, halo, trifiuoromethylpyridines (U.S. Pat. 3,609,158). Other trihalo-containing pyridines are taught in Chemistry of Pyridine Derivatives by Edwin Klingberg (Interscience, 1961), specifically in part 2, pp. 39899.

Pyridyl azides with cyano substituents may be prepared, for instance, from 4-NR (R is H or alkyl)-2- cyano-3,5,6-trichloropyridine (U.S. Pat. 3,285,925); haloand cyano-substituted pyrdines are made according to the process taught in US. Pat. 3,420,833; polybromo, cyanopyridines (U.S. Pat. 3,595,868); chlorocyanopyridines (U.S. Pat. 3,591,597); and, polychloro, monoor dicyanopyridines (U.S. Pat. 3,325,503).

COOH-, COOR- or CONR -Substituted pyridyl azides may be prepared from, for instance, 4-NR' (R is H or alkyl)-2-COOH or CONR -3,5,6-trichloropyridines (U.S. Pat. 3,285,925 3,6-dichloropicolinic acid (U.S. Pat. 3,317,549); or Klingsberg, part 3, Pp- 303-07.

4 recrystallized from sec-butyl alcohol for determination of melting point. Caution was exercised due to the expectation of impact and friction sensitivity.

Melting point was found to be 99.5--103.5 C., and analysis showed the sample to be tetraazidopicolinonitrile.

EXAMPLES 2-13 In a manner similar to Example 1, the following pyridyl azide compounds were prepared by reacting the proper pyridine with NaN Starting material and conditions are listed in the following table:

Solvent and Grams Ex. No.

Reaction Time Temp.,

Starting material and weight used amount NaNa (hours) C.) Pyridyl azide recovered 2 0.05molesoipentachloropyrldine. 150 ml., DMF... 2 90 3,5-dichloro-2,4,6-triazidopyridine. 3 0.2 moles of pentach1oropyridine.- 375 ml., DMF... 3 70 4-azido-tetrachloropyridine. 4 1.12 of tetrachloropicolinie 100 ml., DMF... 1. 12 24 65 B-azido-trichloropicolinic acid.

aci 5 8.4 gm. of 2,4,6-trlbromopyridine 50 ml., DMF 1.63 36 25 75 mole percentl-azido-2,6dibromopyridine 25 mole percent-4,6-diazido-2-bromopyridine. 6 18.2 gm. of 2,3,6-trichloropyridine.. 100 ml., DMF.-- 6. 5 72 60 2,6-diazido-3-chloropyridine. 7 30.4digm. of 2,3,4,6-tetrachloropy- 450 ml, MoOH.. 9.1 72 60 4-azido-2,8,5-trichloropyridine.

n ne. 8 5gm.%i2,4,6-trifiuoro-3,fi-dichloro- 50m1., DMF---. 1.63 36 25 4-azido-2,6-difluoro-3,fi-dlchloropyridine.

pyn ne. 9 70.5 of tetrachloro-2-cyano- 500 ml., MeOH.. 18.8 18 25 4-azido-2-cyanotrichloropyridine.

pyn ne. 10".-. 12.1 of tetrachloro-4-cyano- 501111., DMF..-- 3. 18 2-azido-4-cyanotrichloropyridine.

py'n ne. 11--- 12.1 of tetrachloro-ii-cyanm 50 mL, DMF-.-- 3.3 18 80 6-azido-3-cyanotrlchloropyriine.

pyn ne. 12--...- 23.8 lot tetachloro-2-trichloro- 250 mL, DMF... 6.96 24 25 4,6-diazido-3,5-dichloro-2-trichloromethylpyridine.

met ypyri ne. 13.. 0.02 mole of 2,6-b1s(trichloro- 150 ml., DMF..- 24 25 80 mole percent 4-azido-3,5-dichloroand 20 mole percent methyD-trichloropyridine. 4,bdiazido-3-chloro-2,6-bis(trich1oromethyl)-pyridine.

I 0.264 moles. 2 0.2 moles. 0.022 moles.

the solvent evaporated, and the azide recrystallized from a solvent, such as sec-butyl alcohol.

It is to be noted that the resulting compounds may well be shock and/or friction sensitive. Extreme care should also be taken when heating, particularly as the number of azide groups increases.

Care should be further exercised when elemental analyses are being conducted. Microanalysis can be successfully accomplished providing the microanalyst has sufiicient background regarding the successful combustion of high energy compounds. Adequate shielding of the combustion tube is essential.

The utility of these materials in high energy fuels and detonators is based upon their fuel value as well as direct and reproducible energetics of decomposition. These azides are compatible with hydrazine and the UDMH mixture, thus permitting one to modify the N O -hydrazines liquid propellant system. The impact sensitivity of the polyazide compounds coupled with the completely non-metallic decomposition gases results in reduced fouling and barrel corrosion. Solid propellant formulations, especially for flare applications, are preferred utilities.

SPECIFIC EMBODIMENTS Example 1.-Tetraazidopicolinonitrile 24.2 gm. (0.1 mole) of tetrachloropicolinonitrile was mixed with 32.5 gm. (0.5 mole) of NaN the entire mass then being slurried with 100-150 ml. of dimethylformamide (DMF). The material dissolved upon heating to 60 C., whereupon it was stirred at that temperature for 18 hours.

The solution, which contained suspended NaCl, was poured into ice water and the solids were filtered and washed with water several times. A small quantity was EXAMPLE 14 wherein each X is independently Cl, Br or F; m is 1 to 4; n is 0 to 3; and m+n is 1 to 4.

2. Tetraazidopicolinonitrile.

3. The compound of claim 1 wherein X is Cl.

References Cited FOREIGN PATENTS 1,161,492 8/1969 Great Britain 260294.8 F

ALAN L. ROTMAN, Primary Examiner US. Cl. X.R.

149l09; 260295 AM, 295 R, 295.5 A, 295.5 R, 296 R, 296 H mg STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,773,77 Dated November 20, 1973 Inventor(s) Calvin E. Pannell It is certified that error appears in the above-identified paten and that said Letters Patent are hereby corrected as shown below:

Column l, line 12 'in Table, Example No. 11 under "Pyridyl azide r should read.

-- 6-azido-3-eyanotrichloropyridine.

Column line +6 formula should be:

Signedv and sealed this 26th ,day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer Coxmnissioner of Patents gz gg UNITED STATES PATENT OFFICE I CERTIFICATE OF CORRECTION Patent 3,7733% Dated November'20, 1973 Inventofls) 7 "Calvin E. Pannell It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:-

Column l, line 12 in Table, Example No. 11 under "Pyridyl azid-e reco should read 6 9.2ido-3-cjanotrichloropyridine.

Column +6 Should be:

-*- XII, (1x1 NY ON Signed and sealed this 26th day of November 1974.

(SEAL) Attest: v

McCOY M. GIBSON JR. c. MARSHALL DANN h Attesting Officer Commissioner of Patents 

